1. Field of the Invention
The present invention is related to knitting needles for knitting sueded fabrics, the needles having at least one abrasive surface.
2. Description of Related Art
In the textile industry, it is known to finish certain woven, weft knitted, and warp knitted fabrics by abrading one or both surfaces of the fabric. The knitted fabric is abraded using sandpaper or a similarly abrasive material to cut and raise the constituent surface of the yarns knitted in the fabric into a closely raised nap, producing a soft, smooth surface texture resembling suede leather. This operation is commonly referred to as sueding, sanding, brushing, emerising, or napping (hereinafter “sueding” or “sueded”).
Sueding is conventionally performed by a specialized fabric machine that passes a knitted fabric over one or more finishing rolls, normally after the fabric has been dyed. The finishing rolls are covered with abrasive material and are rotated rapidly against the surface of the fabric. Unfortunately, conventional sueding operations have several significant disadvantages.
For example, conventional sueding processes require the knitted fabric to undergo one or more separate sueding processes after the knitting process, which can increase the cost of the resultant fabric.
In addition, conventional sueding machines necessarily cause a substantial amount of fibrous lint and fly, abrasive dust, and the like to be released from the fabric and the abrasive rolls (hereinafter “debris”). The debris can become airborne, posing a health hazard to machine operators. In addition, the debris may become embedded in the interstices of the fabric, detracting from its surface finish. Still other of the debris may accumulate on the abrasive surface of the finishing rolls, tending to negate at least somewhat their abrasive sueding effect.
Further, conventional sueding machines are typically limited in their operational widths to the processing of fabrics no greater on average than 60 to 65 inches in width. On the other hand, many conventional weaving and warp knitting machines are available for producing fabrics in widths two to three times or more greater in width than the effective operating width of conventional sueding equipment. Thus, when it is desired to produce a suede finish on fabrics of such greater widths than the maximum widthwise finishing capability of sueding machines, it is necessary to initially cut the fabric lengthwise into a least two smaller width lengths which are then individually processed through a sueding machine. Subsequently, the cut fabric must then be rejoined.
Still further, conventional sueding machines can produce streaks within the resultant fabric. These are relatively lighter or darker lines that appear in the warp direction. While these may be due to fabric or yarn irregularities, they may also occur due to random variation in the grit particles on the sueding machine. If a particularly large or aggressive particle is present in a particular location on the sueding machine, more fibers will be cut in that area such that lighter colored fibers in the yarn core may be exposed in that area, producing a streak. One method of mollifying the effect of individual grit particles is to make the abrasive drum very large so that the effect of a single grit particle is not continuous. However, this method reduces the pressure of the fabric against the treatment roll, requiring either relatively coarse grit, or some other means to create pressure, such as through the utilization of flaps, backup rolls, or air pressure. Another method to make the streak more difficult to observe is to oscillate the treatment rolls along the rotational axis, which creates a sinusoidal pattern on the fabric, so that the effect of single grit particles is spread out. Oscillation is often used in multi-roll treatment machines, with the oscillations timed so as not to be superimposed. All of these processes require specialized equipment that tends to further increase the cost of the resultant fabric.
Another common problem with conventional sueding processes is that the cutting of fibers reduces the tensile properties of the fabric, regardless of yarn type.
In addition, since the sueding is conventionally performed after the fabric has been dyed there is also typically a shade change from the dyed product to the sueded one, which can be difficult to control.
Accordingly, there is a need for sueded fabrics and methods of knitting such fabrics that overcome and/or mitigate one or more of the aforementioned deleterious effects of the prior art.